Alkaline dishwasher detergent



United States Patent 3,544,473 ALKALINE DISHWASHER DETERGENT Everitt A.Kitchen and Judith K. Simmons, Cincinnati,

Ohio, assignors to The Procter & Gamble Company,

Cincinnati, Ohio, a corporation of Ohio No Drawing. Filed Sept. 6, 1968,Ser. No. 758,121

Int. Cl. C11d 7/56 US. Cl. 252-99 3 Claims ABSTRACT OF THE DISCLOSUREAlkaline dishwasher detergent based on an alkaline sequestrant builder,sodium silicate, a chlorine bleach, an alcohol ethoxylate nonionicsurfactant and an insoluble phthalocyanine green dye.

BACKGROUND Since the introduction of mechanical dishwashing equipment,considerable attention has been directed to the improvement of alkalinedishwasher detergents. To obtain efficient cleaning in mechanicaldishwashers, the detergent used therein must be well formulated. Suchdetergents should contain an alkaline sequestrant builder salt, sodiumsilicate, a chlorine bleach and a nonionic surfactant. Most dishwasherdetergents employ nonionic surfactants which are based on propyleneoxide/ethylene oxide condensation products.

It has been found desirable to include a dye in dishwasher detergents inorder to identify it as a dishwasher detergent and thereby avoid itsconfusion with other white granular products used in the kitchen.Avoidance of such confusion is desirable because dishwasher detergentsnecessarily are alkaline and contain a chlorine bleach. Be cause ofthese components an effort should be made to change its appearance fromother white kitchen powders such as sugar, salt, cornstarch and thelike. A very useful color for this purpose is green, particularlybecause of the traditional association of green with chlorine bleach,chlorine gas being green colored. Moreover, housewives associate greenin their minds with an ability to clean well. The most suitable andreadily available green dye is insoluble phthalocyanine green. It hasbeen found, however, that when insoluble phthalocyanine green is usedwith the nonionic surfactants of condensed propylene oxide/ethyleneoxide, severe straining problems are encountered. These problems involvethe green staining of plastic tableware and plastic dishwasher partsafter a few months usage. Because of this staining problem it has beennecessary to use the more expensive and less available solublephthalocyanine green dyes in conjunction with the propyleneoxide/ethylene oxide nonionics.

It is, therefore, an object of this invention to provide a dishwasherdetergent employing a specific type of nonionic surfactant whichsurprisingly permits the use of the readily available insolublephthalocyanine green dye without encountering the expected stainingproblems on plastic tableware and dishwasher parts.

DESCRIPTION OF THE INVENTION This invention is an alkaline dishwasherdetergent composition comprising an alkaline sequestrant builder salt,sodium silicate, a chlorine bleach, insoluble phthalocyanine green dyeand, as a nonionic surfactant, the condensation product of 0 -0 normalfatty alcohol with from 5 to 12 moles of ethylene oxide. This dishwasherdetergent is effective and has a pleasing and useful green color butdoes not, in use in a mechanical dishwasher, result in objectionablestaining of plastic dinnerware and dishwasher parts.

The alkaline sequestrant builder salt is a primary cleaning component ofthe dishwasher detergent and is employed in an amount ranging from 25%to preferably 35% to 60%, of the composition. It also sequesters waterhardness to preclude deposition of hardness salts on the kitchenwarebeing washed. Organic or inorganic sequestrant builder salts or mixturesthereof can be used. The preferred sequestrant builder salt classes arethe alkali metal (e.g., sodium and potassium) inorganic polyphosphates,organic aminopolyacetates and organic polyphosphonates. Specificexamples of these preferred builder salts are sodium tripolyphosphate,tetrasodium pyrophosphate, triand tetra-sodium ethylene diaminetetraacetate, trisodium nitrilotriacetate, trior tetra-sodium ethanelhydroxy-Ll-diphosphonate and triand tetra-sodiumethane-l-hydroxy-1,1,2-triphosphonate. Additional examples of such saltsare found in Zimmerers U.S. Pat. 3,351,558, especially from line 64,column 2 to line 38, column 3 which is incorporated herein by reference.

The sodium silicate is employed in the dishwasher detergents also as aprimary cleaning ingredient, as a source of alkalinity, as an inhibitorof metallic corrosion and as a protector of glaze on china tableware. Itis used in an amount ranging from 5% to 50%, preferably 10% to 25% ofthe composition and has a SiO :Na O ratio ranging from about 3.611 toabout 1:1, preferabl from 3:1 to 1:1.

The chlorine bleach component is a compound which contains chlorine inan active form. Such compounds are often characterized as hypochloritecompounds and are well known as a class. The dishwasher detergent shouldcontain 0.5% to 25% of an active chlorine-containing bleaching compound,perferably 1% to 15%. Examples of such compounds are: dichlorocyanuricacid; 1,3-dichloro-5,5-dimethyl hydantoin; N,N-dichlorobenzoylene urea;paratoluene sulfondichloroamide; trichloromelamine; N-chloroammeline;N-chlorosuccinirnide; N,N- dichloroazodicarbonamide; N-chloroacetylurea; N,N'-dichlorobiuret; chlorinated dicyandiamide; sodiumhypochlorite; calcium hypochlorite; lithium hypochlorite; chlorinatedtrisodium phosphate. Preferred compounds are chlorinated trisodiumphosphate and sodium and potassium dichlorocyanurate. The termchlorinated trisodium phosphate is used to designate a compositionconsisting of trisodium phosphate and sodium hypochlorite in intimateassociation in a crystalline form. The chlorinated trisodium phosphatecan contain from 1% to 5% available chlorine (calculated on the basis ofthe hydrated material) and may be prepared by the methods of US. LettersPatent 1,555,474 or 1,965,304, or modifications thereof.

Phthalocyanine green dye is an organic pigment having as a structuralunit four isoindole groups (C HQC N, linked by four nitrogen atoms so asto form a conjugated chain. The expensive, and not readily-available,soluble phthalocyanine green dye has the following structural formula:

The less expensive and more readily-available phthalocyanine green dyeof the composition of this invention has the following formula:

It is used in the detergents of this invention in an amount ranging from0.001% to 0.015%, preferably 0.002% to 0.01%. Lesser amounts do notprovide a desired green color in the composition and greater amounts areunnecessary and would tend to cause stain problems notwithstanding theunexpected advantages provided with specific nonionic surfactantdescribed below.

The nonionic surfactants employed in the dishwasher detergents of thisinvention, the use of which surprisingly overcomes the plastic tablewarestaining tendencies of insoluble phthalocyanine green dye, are C -Cnormal fatty alcohol-ethylene oxide condensates, i.e., condensationproducts of one mole of a fatty alcohol containing from 13 to 21 carbonatoms with from to 12, preferably 6 to 11, moles of ethylene oxide. C Calcohol such as tallow fatty alcohol is preferred in the condensates. Itusually comprises a mixture of 65% octadecanol, 33% hexadecanol and 2%tetradecanol, but can vary, depending on the tallow source. Smallamounts up to 10% of C and C alcohols can be tolerated but at least 90%must be C C to obtain good cleaning without undue sudsing. Suchcondensates are well known in the detergent art but are not believed tohave been used, prior to this invention, in dishwasher detergentscontaining insoluble phthalocyanine green dye. Prior attempts to useinsoluble phthalocyanine green dye in dishwashing detergents, involvingthe use of propylene oxide containing nonionic surfactants, haveresulted in objectionable plastic tableware and dishwasher partsstaining problems. Why the higher alcohol/ethylene oxide condensates ofthe compositions of this invention solve this plastic staining problemis not known, but the solution thereto was unexpected. Thesealcohol/ethylene oxide condensates are employed in an amount rangingfrom /2 to 10%, preferably from 1% to 5% of the composition.

The compositions of this invention have a pH in the range of 9.7 to 12.1(measured in 1% aqueous solution) in order to obtain satisfactorycleaning in the dishwasher. They can be prepared by dry-mixing theingredients or by agglomeration processes such as those described in US.Patent 2,895,916, Milenkevich, issued July 21, 1959, incorporated hereinby reference.

The instant dishwasher detergents can contain minor amounts of optionalingredients such as perfume, suds depressants such as monoor di-stearylacid phosphate or silicones, inert salts such as NaCl or sodium sulfate,anti-tarnish agents such as benzotriazole and aluminum salts, enzymes,alkaline agents such as caustic soda, or sodium carbonate, anticakingagents such as urea. Preferably from 0.1% to 1% monoand/ or di-stearyland phosphates are used, desirably as the sodium salt.

The percentage figures listed above for the ingredients are on a drybasis. In practice the compositions preferably contain significantamounts of Water as water of hydration. This water can be in amountsfrom 0% to 35% of the composition.

Below are working examples illustrative of the compositions of thisinvention which should not be considered as limiting. All parts,percentages and ratios used in the specification, examples and claimsherein are by weight unless otherwise specified.

EXAMPLE I A dishwasher detergent composition is prepared by thefollowing procedure:

parts of anhydrous granular sodium tripolyphosphate,

and

14 parts of sodium silicate having an SiO :Na O ratio of 2.9:1 areplaced in a mixer and thoroughly mixed,

27.6 parts of water are then added to this mixture and blended in toagglomerate the tripolyphosphate-silicate mixture,

9.7 parts of chlorinated trisodium phosphate (calculated on an anhydrousbasis and containing 7.5% available chlorine) are then added to themixture with agitation. The added water all hydrates into theingredients of the mixture. The following additives are then blendedinto the mixture with agitation:

0.8 part sodium monostearyl acid phosphate,

.007 part insoluble phthalocyanine green dye, and

2.6 parts of the condensate of one mole of tallow fatty alcohol and 9moles of ethylene oxide. The resultant green-colored detergent has a pHof 10.6 and cleans soiled plastic tableware effectively in a mechanicaldishwasher, but without staining on repeated usage.

The same composition was prepared except that the tallowalcohol/ethylene oxide condensate was replaced with the condensationproduct of ethylene oxide with a hydrophobic base formed by condensingpropylene oxide with propylene glycol, the product having a molecularweight of 4000. This compoistion, as changed to represent the prior art,cleaned well, but resulted in severe plastic dinnerware stainingproblems in just a few months usage time.

EXAMPLE II The following dishwasher detegent is prepared by dry mixingthe listed ingredients.

45% sodium tripolyphosphate (anhydrous basis),

3.5% potassium dichlorocyanurate,

2.6% condensation product of one mole of tallow fatty alcohol and ninemoles of ethylene oxide,

0.8% mixture of monoand di-stearyl acid phosphate,

sodium salt,

20% sodium meta silicate (having an SiO :Na O ratio 15.5% sodiumsulfate,

0.007% insoluble phthalocyanine green dye,

balance water, as water of hydration in the sodium tripolyphosphatewhich was prehydrated before admixture.

The resulting composition is an excellent alkaline dishwasher detergenthaving a green color and a pH of 10.6 in 1% aqueous solution. It cleanssoiled dishes very well in a mechanical dishwasher, resulting in nonoticeable staining of plastic dinner ware or dishwasher parts inseveral months time.

The following are additional examples of dishwasher detergents whichhave a pleasing and useful green color and which clean soiled plastictableware in a mechanical dishwasher having plastic parts withoutstaining either. They have a pH of about 10.5.

EXAMPLE III trisodium nitrilotriacetate,

15% sodium silicate having an SiO :Na O ratio of 2.1 1,

10% potassinm dichlorocyanurate,

2% condensation product of 1 mole of octadecanol and 10 moles ofethylene oxide,

0.005% insoluble phthalocyanine green dye, balance, water as moistureand water of hydration.

EXAMPLE IV EXAMPLE V 50% trisodium ethane l-hydroxy-l,l-diphosphonate,

% sodium silicate having an SiO :Na O ratio of 1.6: l,

3% condensation product of 1 mole of tallow fatty alcohol and 6 moles ofethylene oxide,

0.01% insoluble phthalocyanine green dye,

balance, water of hydration and moisture.

EXAMPLE VI 10% tetrasodium ethane-l-hydroxy-l,1,2-triphosphonate,

% trisodium nitrilotriacetate,

15% sodium silicate having an SiO :Na O ratio of 2.6: 1,

10% calcium hypochlorite,

2% condensation product of 1 mole of nonadecanol and 9 moles of ethyleneoxide,

.005 insoluble phthalocyanine green dye,

balance, water of hydration and moisture.

What is claimed is: 1. An alkaline dishwasher detergent compositionconsisting essentially of:

(a) 25% to 75% alkaline sequestrant builder salt selected from the groupconsisting of an inorganic polyphosphate, an organic aminopolyacetate,or an organic polyphosphonate,

(b) 5% to sodium silicate having an SiO :Na O

ratio ranging from 3.6:1 to 1:1,

(0) 0.5% to 25 active chlorine containing bleaching compound,

((1) /2% to 10% condensation product of 1 mole of (E -C fatty alcoholwith 5 to 12 moles of ethylene oxide, and

(e) 0.001 to 0.015% insoluble phthalocyanine green dye percentage byweight.

2. The composition of claim 1 wherein the builder salt is in an amountof 35% to the silicate in an amount of 10% to 25 the chlorine-containingbleaching compound is chlorinated trisodium phosphate, or sodium orpotassium dichlorocyanurate and the amount thereof is 1% to 15%; thecondensation product is of 1 mole of C C fatty alcohol with 6 to 11moles of ethylene oxide.

3. The composition of claim 2 wherein the builder salt is sodiumtripolyphosphate, the bleaching compound is chlorinated trisodiumphosphate, the alcohol in the condensation product is tallow fattyalcohol and the amount of green dye is 0.002% to 0.01%.

References Cited UNITED STATES PATENTS MAYER WEINBLATI, Primary ExaminerU.S. Cl. X.R. 252-187

